If it's normal IDE interrupt, BSY bit will always be 0 (unless the
interrupt is shared with some other device)...

+ /*
+ * We are busy, try to handle
+ * it later. This is the DMA
+ * finished interrupt, and it
+ * could take a little while
+ * for the card to be ready
+ * for more commands.
+ */
+ cf_port = (struct octeon_cf_port *)ap->private_data;
+ tasklet_schedule(&cf_port->delayed_irq_tasklet);